ia32.c revision 253734 
1169689Skan/* Licensed to the Apache Software Foundation (ASF) under one or more
2169689Skan * contributor license agreements.  See the NOTICE file distributed with
3169689Skan * this work for additional information regarding copyright ownership.
4169689Skan * The ASF licenses this file to You under the Apache License, Version 2.0
5169689Skan * (the "License"); you may not use this file except in compliance with
6169689Skan * the License.  You may obtain a copy of the License at
7169689Skan *
8169689Skan *     http://www.apache.org/licenses/LICENSE-2.0
9169689Skan *
10169689Skan * Unless required by applicable law or agreed to in writing, software
11169689Skan * distributed under the License is distributed on an "AS IS" BASIS,
12169689Skan * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13169689Skan * See the License for the specific language governing permissions and
14169689Skan * limitations under the License.
15169689Skan */
16169689Skan
17169689Skan#include "apr_arch_atomic.h"
18169689Skan
19169689Skan#ifdef USE_ATOMICS_IA32
20169689Skan
21169689SkanAPR_DECLARE(apr_status_t) apr_atomic_init(apr_pool_t *p)
22169689Skan{
23169689Skan    return APR_SUCCESS;
24169689Skan}
25169689Skan
26169689SkanAPR_DECLARE(apr_uint32_t) apr_atomic_read32(volatile apr_uint32_t *mem)
27169689Skan{
28169689Skan    return *mem;
29169689Skan}
30169689Skan
3118334SpeterAPR_DECLARE(void) apr_atomic_set32(volatile apr_uint32_t *mem, apr_uint32_t val)
3218334Speter{
3318334Speter    *mem = val;
3418334Speter}
3518334Speter
3618334SpeterAPR_DECLARE(apr_uint32_t) apr_atomic_add32(volatile apr_uint32_t *mem, apr_uint32_t val)
3718334Speter{
3818334Speter    asm volatile ("lock; xaddl %0,%1"
3918334Speter                  : "=r" (val), "=m" (*mem)
4018334Speter                  : "0" (val), "m" (*mem)
4118334Speter                  : "memory", "cc");
42169689Skan    return val;
4318334Speter}
4418334Speter
45169689SkanAPR_DECLARE(void) apr_atomic_sub32(volatile apr_uint32_t *mem, apr_uint32_t val)
46169689Skan{
47    asm volatile ("lock; subl %1, %0"
48                  : /* no output */
49                  : "m" (*(mem)), "r" (val)
50                  : "memory", "cc");
51}
52
53APR_DECLARE(apr_uint32_t) apr_atomic_inc32(volatile apr_uint32_t *mem)
54{
55    return apr_atomic_add32(mem, 1);
56}
57
58APR_DECLARE(int) apr_atomic_dec32(volatile apr_uint32_t *mem)
59{
60    unsigned char prev;
61
62    asm volatile ("lock; decl %0; setnz %1"
63                  : "=m" (*mem), "=qm" (prev)
64                  : "m" (*mem)
65                  : "memory");
66
67    return prev;
68}
69
70APR_DECLARE(apr_uint32_t) apr_atomic_cas32(volatile apr_uint32_t *mem, apr_uint32_t with,
71                                           apr_uint32_t cmp)
72{
73    apr_uint32_t prev;
74
75    asm volatile ("lock; cmpxchgl %1, %2"
76                  : "=a" (prev)
77                  : "r" (with), "m" (*(mem)), "0"(cmp)
78                  : "memory", "cc");
79    return prev;
80}
81
82APR_DECLARE(apr_uint32_t) apr_atomic_xchg32(volatile apr_uint32_t *mem, apr_uint32_t val)
83{
84    apr_uint32_t prev = val;
85
86    asm volatile ("xchgl %0, %1"
87                  : "=r" (prev), "+m" (*mem)
88                  : "0" (prev));
89    return prev;
90}
91
92APR_DECLARE(void*) apr_atomic_casptr(volatile void **mem, void *with, const void *cmp)
93{
94    void *prev;
95#if APR_SIZEOF_VOIDP == 4
96    asm volatile ("lock; cmpxchgl %2, %1"
97                  : "=a" (prev), "=m" (*mem)
98                  : "r" (with), "m" (*mem), "0" (cmp));
99#elif APR_SIZEOF_VOIDP == 8
100    asm volatile ("lock; cmpxchgq %q2, %1"
101                  : "=a" (prev), "=m" (*mem)
102                  : "r" ((unsigned long)with), "m" (*mem),
103                    "0" ((unsigned long)cmp));
104#else
105#error APR_SIZEOF_VOIDP value not supported
106#endif
107    return prev;
108}
109
110APR_DECLARE(void*) apr_atomic_xchgptr(volatile void **mem, void *with)
111{
112    void *prev;
113#if APR_SIZEOF_VOIDP == 4
114    asm volatile ("xchgl %2, %1"
115                  : "=a" (prev), "+m" (*mem)
116                  : "0" (with));
117#elif APR_SIZEOF_VOIDP == 8
118    asm volatile ("xchgq %q2, %1"
119                  : "=a" (prev), "+m" (*mem)
120                  : "0" (with));
121#else
122#error APR_SIZEOF_VOIDP value not supported
123#endif
124    return prev;
125}
126
127#endif /* USE_ATOMICS_IA32 */
128